Intrinsic pre-sodiation of lignin-based ultrafine carbon fibers for sodium-ion battery anode

Jingke Zhang; Haitao Ren; Baoxu Wang; Zhiwei Cao; Hengxue Xiang; Shichao Wang; Meifang Zhu

doi:10.1016/j.ijbiomac.2025.145541

Intrinsic pre-sodiation of lignin-based ultrafine carbon fibers for sodium-ion battery anode

Int J Biol Macromol. 2025 Jun 25:145541. doi: 10.1016/j.ijbiomac.2025.145541. Online ahead of print.

Authors

Jingke Zhang¹, Haitao Ren¹, Baoxu Wang¹, Zhiwei Cao¹, Hengxue Xiang², Shichao Wang³, Meifang Zhu²

Affiliations

¹ College of Materials Science and Engineering, Qingdao University, Qingdao 266071, China.
² State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
³ College of Materials Science and Engineering, Qingdao University, Qingdao 266071, China. Electronic address: wangsc@qdu.edu.cn.

PMID: 40578628
DOI: 10.1016/j.ijbiomac.2025.145541

Abstract

Hard carbon-based sodium-ion batteries (SIBs) anodes still face a significant challenge that the oxygen-containing functional groups and inherent defects result in an irreversible natrization during the initial charging process. The pre-sodiation strategy is designed to compensate for the consumption of sodium ions, typically achieved by adding sodium ion supplements. In this study, we propose an intrinsic pre-sodiation strategy based on hardwood kraft lignin (HKL), which is extracted using sodium hydroxide (NaOH) and sodium sulfide. Self-supported HKL ultrafine carbon fiber anodes with varying sodium contents (HKL-NaX-CFs) were prepared successfully through electrospinning, stabilization, and carbonization. The effects of NaOH on HKL under the dual influences of pre-sodiation and activation was investigated systematically, including the interaction between NaOH and HKL, the thermal properties of HKL, the morphology, microcrystalline structure and electrochemical properties of HKL-based ultrafine carbon fibers (HKL-CFs). Results indicate that pre-sodiation strategy increased the layer spacing of graphite lamella, pore volume, and diffusion-controlled capacity of HKL-CFs, leading to better capacity and rate performance. Notably, the HKL-Na2-CF anode exhibited a capacity of 231.7 mAh g^-1 at 30 mA g^-1 and 68.3 mAh g^-1 at 2000 mA g^-1. The intrinsic pre-sodiation strategy offers an inspiration for the supplement of sodium ions.

Keywords: Lignin-based ultrafine carbon fibers; Pre-sodiation; Sodium ion battery.